This study investigates the influence of demographic factors on use of online library resources by undergraduate students in two private Nigerian university libraries. Descriptive survey design was adopted for the study and the study population consisted of 7500 undergraduates from Babcock University and 2200 from Redeemer’s University. Random sampling was used to select a sample of 291 and questionnaire was the main instrument used for data collection. Data was analyzed using descriptive statistics consisting of tables of frequency and percentage for the demographic characteristics and spearman non-parametric correlation was used for the hypotheses. The findings revealed that there was significant relationship between level of study and utilization of online library resources (r=.933.; P= <0.05) and age and use of online library resources (r=.44.; P>0.05). There was no significant relationship between gender and use of online library resources (r=.95.; P<0.05) and between religion and use of online library resources (r=.46.; P>0.05). The internet and e-journals were important sources of information for the university undergraduate students. Students’ demographic factors should not be a barrier to e-resources use and as a result, students of all ages and gender should endeavor to acquire knowledge required to enable them make effective use of online library resources anytime and anywhere. Both young and old students should be encouraged and sensitized on the benefits available in the use of library online resources.